SIGNAL TRANSDUCTION EVENTS AND THE REGULATION OF CELL GROWTH

这个项目是为了增加我们对生物的了解 前列腺癌和开发治疗前列腺癌的新方法 晚期前列腺癌的信号转导研究 调节人前列腺癌细胞系生长的事件。 这项工作目前集中在(1)cAMP对生长和 分化，(2)通过激活P2-嘌呤能产生的细胞毒性 受体；(3)HMG-CoA还原酶的抗癌活性。 洛伐他汀抑制剂。我们发现细胞内cAMP的升高 对所有测试的前列腺癌细胞系都有高度的生长抑制作用。 为了研究cAMP在前列腺癌细胞中的作用机制 检测cAMP类似物二丁酰cAMP对肌动蛋白表达的调节作用 强大的负生长因子转化生长因子-β。选择性诱导DbcAMP 前列腺癌细胞分泌转化生长因子-β2，而不是转化生长因子-β1。 这种转化生长因子-β2在CCL-水貂肺细胞上被证明具有生物活性。 化验。Northern分析表明，DBcAMP诱导了细胞周期的增加。 5个特征性的转化生长因子-β2转录本。因此，dbcAMP会导致 前列腺癌细胞表达具有生物活性的转化生长因子-β2 前列腺癌治疗的新途径和新分子 CAMP作用机制。P2-嘌呤能受体研究证实 雄激素非依赖性前列腺癌细胞表达P2-嘌呤能 与磷脂酶C激活、急性钙离子偶联的受体 动员，延长细胞质和细胞核钙振荡，生长 被捕，以及细胞死亡率的增加。相比之下， 雄激素敏感细胞的表面P2受体是解偶联的 从磷脂酶C、钙离子动员和生长停滞。在……里面 与分子病理生理学分会合作，我们发现 雄激素敏感细胞缺乏G蛋白α亚单位的表达 已经被证明与磷脂酶C偶联。这些数据很强 磷脂酶C激活与钙离子动员时间延长的关系 P2激动剂的生长抑制作用，并提供了一种分子 雄激素敏感中P2受体解偶联的机制 细胞。对HMG-CoA还原酶抑制剂洛伐他汀的研究表明 洛伐他汀对人前列腺癌细胞有细胞毒作用。我们发现 洛伐他汀治疗可显著降低转化生长因子-β2的表达 肿瘤组织中信使核糖核酸的合成及蛋白表达的失控 抑制基因产物pRb。

This project is designed to increase our understanding of the biology of prostate cancer and to develop a new approach to the treatment of advanced prostatic cancer through the study of the signal transduction events regulating the growth of human prostate carcinoma cell lines. This work is currently focused on (1) effects of cAMP on growth and differentiation, (2) cytotoxicity through activation of P2-purinergic receptors, and (3) the anticancer activity of the HMG-CoA reductase inhibitor lovastatin. We have found that elevation of intracellular cAMP is highly growth-inhibitory to all prostate carcinoma cell lines tested. To examine the mechanism of cAMP action in prostate carcinoma cells we tested the effect of the cAMP analog dibutyryl cAMP on the regulation of the potent negative growth factor TGF-beta. DbcAMP selectively induced the secretion of TGF-beta2 and not TGF-beta1 by prostate carcinoma cells. This TGF-beta2 was shown to be bioactive using the CCL-64 mink lung cell assay. Northern analysis showed that dbcAMP induced an increase in the five characteristic TGF-beta2 transcripts. Thus dbcAMP induces the expression of bioactive TGF-beta2 by prostate carcinoma cells, suggesting a new approach to the treatment of prostate cancer and a new molecular mechanism of cAMP action. P2-purinergic receptor studies demonstrated that androgen-independent prostate carcinoma cells express P2-purinergic receptors that are coupled to phospholipase C activation, acute Ca2+ mobilization, prolonged cytoplasmic and nuclear Ca2+ oscillations, growth arrest, and an increased rate of cell death. In contrast, androgen-sensitive cells have surface P2 receptors that are uncoupled from phospholipase C, Ca2+ mobilization and growth arrest. In collaboration with the Molecular Pathophysiology Branch we found that the androgen-sensitive cells lack expression of G protein alpha subunits that have been shown to couple to phospholipase C. These data strongly implicate phospholipase C activation and prolonged Ca2+ mobilization in the growth-inhibitory effect of P2 agonists, and provide a molecular mechanism for the uncoupling of the P2 receptor in androgen-sensitive cells. Studies with the HMG-CoA reductase inhibitor lovastatin showed that lovastatin is cytotoxic to human prostate carcinoma cells. We found that lovastatin treatment results in marked deregulation of TGF-beta2 mRNA synthesis and in deregulation of protein expression of the tumor suppressor gene product pRB.